SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ee330a31335b1f9028406df5eb61f926ad1462333c1d68c927412030db931e9' 
  AND token = 'jc1UOPii6deq4eYIOy578ICz9wy6UX33CsXTqKruDE4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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