SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3247a24ed0dcc53fa018afed00dbfaa36b2711bb629f305fac802f19c52509f6' 
  AND token = 'fy/wt1fk7VuwlMx8twkRnBgNACkrVSa9rKXbjbjhAYU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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