SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a8b3d85f575f33b77fffa464e4fccb060c7b39db1feedfcc676d334ab299b176' 
  AND token = '28zeJ1IDYDKTumaJVNWbkKQHmnR/0+J2f7dziqvsyEw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}