SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f9d6f80b08a13ce79fd0b11c82c494ce0b7b0cc59d5233818731541feffb3e0' 
  AND token = '4jQm7X80dYcACrwdT6VmGKiDgcePi0l7Gr7TnHC4rz4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}