SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2141d18c5b9e6392b6d82846c2ba1e621d0333be01ebb9ed7ffdce6bb139acca' 
  AND token = 'DaU4uExy84m7UJ1Mrh5x0aFCkMNqJHu9QHC/kMz7kOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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