SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3552e0e49137f421b459dee2f24e7b28be23ea5ce972932b9a87da0c6345682d' 
  AND token = 'CRD45SIbrxH6O/HwqLYh2JGBnVMjJkw0Mz93j8HQV2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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