SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dfe0000b24ea0b25c9de80d90e15190f23e53196fa38166722b9bddf072bf2bf' 
  AND token = 'a3YpumlPNmazZTlHg2YlIqMq6mhp+Y3Y9maLhkdnNa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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