SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd1a1f5e87feca1d6deff1254a879b36736a93aa311f786939f550c5f483636b' 
  AND token = 'vPEZrAfu1IDnr7XKhgqFxRJTgyraEtN0d+Jj4MQR61A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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