SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e227ea87b4754c237a1145a95bf47ad1ff8277861078fbefba20575a543dc203' 
  AND token = 'AaFPNDBrtSSekS+VgpaL30s7FEoS+NOSom9SdnNlRs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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