SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '714cb59dbe3886ff05ff7c6a8a19a382426ddce491cbdf247bc2a17aea106502' 
  AND token = 'McOpsbbVVxQnxAOxQLF2MEtf0Zeyew3RJCmLhEgUsSc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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