SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbd74d3b37aa8abc8319d7ff8d963fc383f5594877ab4bca1313f41cc8d76985' 
  AND token = 'AJbQJht9OvrRClLzAkmD6NQlTg78+05Xq0/UJ78Q2bY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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