SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66a7e49731bc09041d3b04045124fc12bb51e9cafeacd3132ecddf5d0854f258' 
  AND token = 'pBEMPNqeYtzsMtCk/gNPPBhFeyZQzkqqfV19xJSD0a8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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