SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28aca474c4e7614f75a1eed40107511ccb1c01243992a6ccc74298c68a649c3' 
  AND token = 'bzeraGHFQPUS+vUHJbjpmhQNtZdiZXIEgVnL4bDASj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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