SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bbfb793e8201ac45eda7fc5f28b0e8a7db8809a3aaf029eb3fc78d8139216a66' 
  AND token = 'ZJjjcQfD76Qv0bDD3kv+p7En9p8Wbp8JQEPrbZwwkm8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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