SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf5264db25564cb483506412ba83126a6f28746d589c1a4997cd6453a47f24cb' 
  AND token = 'KiPq2N+DeoQk63hrUjsN8ClJHv/N0VkitaOy2W+wpmA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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