SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '953d178421922f6a676f2258bbe560f352186cc9e5fd249679567ca72adc9386' 
  AND token = 'LQ5ZL5SQcngEvP/e4rD94NJoBzdlH71h4n+YxbmyrLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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