SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9687c6c4018ac215057fbb1932eaa994266b0a43cac6a084c3ade38e70e4519' 
  AND token = 'RDyIeniotIXj9qHqkbH4K7SOdWBv2xRYj8plO/NnWGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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