SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b134435f0c2ff0ad522011e9cd7ecfd4b817bf60edcfb445f4d461d84eb07259' 
  AND token = 'hG3oGPvmkcqQjrULi79eYR+B928bJiL1wZ7KxsiuKH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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