SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e08a8402b9a485adea89db9c3132a1d6780d7cfb694bcd2f3ad4e409eaae128' 
  AND token = 'DKNWV0PwW//HKHTBvUaxVW6EzpF6kvXPeN3IK5z2BwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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