SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2844d801b2aaa86639ed2311dcf00bc32ca641c5dd2c6641eb4da2cf885a180' 
  AND token = 'zAZF7YisrPK/bDtH8RXa9PwTs71gclzC6HurTed4in4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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