SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b8fc0687a4718bad7826e72f4296a7cc7c38358fdc158461a1c4c9d77b84e5e' 
  AND token = 'jrQyVQFr1/BMgqhdZrHPpcYlgiOKLJRMKC3BEJRjiCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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