SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88e37510b0153ad36b7a2ce868ed0a694840a832e1a054145b556f3a21a08686' 
  AND token = 'Fxc23dDwDUbQfPZ4Ys6KjDV6DJKi7UkyCugFajOQxPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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