SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b4fba9ba6b3050efafc3a0685abcac8c3ac30a852843c3a1a25148fdff27f235' 
  AND token = '1222KpIT7bXrjpDluFZqUC9pSArvpmzCLmsTWd5G/P4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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