SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1631db55a7476a65875b4e1261352d2c25a8f5b0879bb871a2702c67b1aa4d17' 
  AND token = 'rcunsyFjXAcv9ISLejqczf1qlIz0YD/gsmBPWJnYZD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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