SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a54bf584f82f3514aad00b2856e66b954c8d108de60f7fb2380fbeed68ecad1a' 
  AND token = 'F4KAeucynPv4dvIMA7E7wpYiyCu04wyJ6eQbDruLFD8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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