SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efd4d8b8004136032117a46517a85b42c81d097976be1cce3a1f8093f1bf434d' 
  AND token = 'eex/j+65EeItqQhqBjY7sRrGtNVeaKurIjz4Al78osM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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