SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd432cddf15a40e7fe5acb942823199394cb3aa34e00b3f7535235cb009cf4f3a' 
  AND token = 'ePgPwIRPeDGoqTbgLYpqb/NsfeIba4ID/KFxCm6rD+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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