SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38bff9eafb1495d4011247dcd93c7fd2a1a764d00df58da2e79383e2dacc3d0b' 
  AND token = 'J1yCxMczxZUctFRUVh/Gn24sJhElgQeRI0NVGV22EqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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