SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53444a3792dbab70f2d1e343ab9d650bfa6322da324ebb9ae005b2370f56a7ae' 
  AND token = 'i9cSXtG2oekEyC1kr4JyT3o3Rry2KPNKKn8qljtRnOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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