SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b432779ba36dd7d433c450fcb4a311f53f6966ab45bf6d8a1f9c1bee65edbc' 
  AND token = 'bvUdEjKDpnZlvit7I6YxMIQt/0MDQLB8IvmzjhnL1wE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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