SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92b6b8b6e6a5668c1cd9de83c3f0c41132828855ce94a5c93901d9ff0b0b8758' 
  AND token = 'ehKL2Dt8gchuBWqQ4vlXYjWQMQmYc3zK8vEsULbAXTE=' 
  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"
    }
  }
}