SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef8aeaca2cc8dec845802b6bb6175062e4c2b91a280304629f85d81aadb0fa6d' 
  AND token = '1j7tDBEsUgDEJCTK0unCN5JMOO4zTVqJVljjGCdALAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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