SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2cd555c0fc0019187d882088c1d694a4974399e6fb170bdca912031eb17c423f' 
  AND token = 'fJKDbovTGDdMdrNAY6gEIaAkoCtAjGlCIndFygrh4Fk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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