SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e687ceefa08c74f804563ab62039d2ef459e236321fb7b21ceb296e180b7bca9' 
  AND token = 'AuLsDJ/NFyTFkLroeXGSujBoju520NBLbrSdWYPXblo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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