SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b923ac48d99b51f6124b3e8409b77b2d3012703adbbcdf284ac36ea8daa913e' 
  AND token = 'mphohyi9l5Ql781hH78gDiPjGbvQ4isW5WW75UdUzQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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