SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4622c355bc2feb03ce65fb6858c7919a4374d9edc81fa7e218ddac64df66f095' 
  AND token = '3VKDAJGouLDVHe0SEjj0JnBDMEgnoI2AgvK+b9CWlc0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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