SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6e297f8ae741198dc69c5cdfdb7b260f4a18ca288ca8609407400ebf0104a7d' 
  AND token = 'p/zBOdZhxfPdHwovcKYLppK5nYT3kq0TNthPmXeRYds=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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