SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce281e4beb5eddd5c00e7d52d16b727db4c0a70837599a75a32615fb7fef754c' 
  AND token = 'Piu6M5wdq9dKNUF5y9l+Gva75A12RhOzgFAsHl1n4OE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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