SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '078fd28fbc1be426aca7fb262926a6872b6371ff11c01123903ebeefc4975b20' 
  AND token = 'rO1hcdK5ssCOUCHgVrko/CdS+1Ny64ahFUQZ/5um0sU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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