SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '941c2c529b225824f2dda47e0b0e9a99ac8a599d05485ef48316899a55724273' 
  AND token = '8CgkXZ5hAskCZ0lgBshE/ekDBxgckJ2yIbXhqT87YUA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}