SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '237b20ea57d2f1bf01cc367e591d56d293515f40900a9ab5eda5351acecf4985' 
  AND token = 'aORqBdn9+mdW+mlA1LI3X5l3Kp06+yhbdK756GiBa6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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