SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a78c67c6605aab3168ab949df602b36bd5fcfbb2a73e766a22f072c2546c7cb' 
  AND token = 'SpDyEqqPTXZNOpayq9Je8PpTIng92wHYwEmTHnNMYSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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