SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c40de2a88c886876816aba277f530cd7bae1fc88fc0f396414edd2439d84bd54' 
  AND token = 'wb05P0yGN5wU2VHnOPEQR5uA3u+ASa/MX21fm5a14/s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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