SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd0f61e21ba21efcce21bd2dc752360a556cce81b363595349ae3ee7ab9765ecd' 
  AND token = 'SUNZ6IjdgBxV/JhfZ0Pn4Uw8BO6A9n2e4WyTQj3Vls8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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