SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a81356fbcbd943d86545620c95dff7d4ed5a4cdf3d12988647b113367e24f8ae' 
  AND token = '+Kzqcqw/Jqts0QTh/3cC6I57kgyb/ETcpjknv4TimQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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