SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad5a4b37a8960bce3c96a4db7e01c0ca2f49049b17f6ad93df6435968f51fd2' 
  AND token = 'dUBjVqPX5EDtQ05esqUT+XgsktInt1TmYOGVyv+f8Mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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