SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'adbd7bc46596c7a70bce8bc1bcde74038e3b81b7cb443e24da66208001b4ff1e' 
  AND token = 'isTcfGGnK5Fqn53CH6qVAmhbvvGvpF6bnw8Qsn0WuoE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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