SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c46a7150576d252d543f6a9095c648b2c11998fc4f19f2c2b84bb8ff26be9b6c' 
  AND token = 'SOBZMUZt97jwoScvX66HkUZrZ88izVYtdFpmRhOqGk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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