SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27ac49b86bcb8f7d9c3ed0c4591aa3254c3610cd7fc351654da61e8fa942488e' 
  AND token = 'QugeRjBl8LhxxDiracUlmhK6bVj6VTYY+KMDeLcEAPI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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