SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e1ba342866f3ff3ad6d6fae529c0fb95fb9bcd60e9f17022b38c9ee63d422db' 
  AND token = 'DqzcgP/4gKA8ayqwBciJwCgtqv7Khfw3Y/Ua7Pf8TpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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