SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5fe4b38b78e1f67a5d52855840bf38ec5bb1faf6dbba9334902a6e16813ef3f' 
  AND token = 'RYFTq13GfMgrfucQYPiwZ0/DJ+MVo6pSzLtGvYqP9DE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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