SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b87a013e7d88f76bd086763d24d605904d0e4bf043dabdd3e45f05dad26db230' 
  AND token = 'cxw4MPx+vhL8H1tUQBSfYWRWONEeGVzGyzuyetYPGX4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00056

JSON explain

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