SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9ebb884dafafa51d962f90a687bc0b60888aa4aae542352e5481cc78b7d6497' 
  AND token = 'PDVWgo94NRaY6sfvYCy/b9mN0BfjlVlBqOA372XIAOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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