SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd889abc114113c3a2c78be9ff6db4bff5d9185704322c8703b3df0bcb6b46387' 
  AND token = 'vKbdhcnMTWIlasobhppiXoRi3yumuOFrdNinWndQ7+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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