SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af67a12cb46098cc168557d742499210b11b59902207db59457ddc50f94a7775' 
  AND token = 'V1gutDln2rk5oY39kXi9cfV4jaIkLkRVK+L2bR6cj3c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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