SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd4ca08bcb5c86506d6716245911f4b2aec48acccbb4bf20f79cd812710c9bf' 
  AND token = '3dGEvNb90xnCwPpp3eabSANVMGjSU68FSOzzTJgV1gc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}