SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '171c251f58301c42654bdac14f40a71f85947a5a73be7d012c2bb15c4e29f4b0' 
  AND token = 'GjOdWbvC6tMTXtNSOpZC9TCS2jNsQEaQAgXxAWnaEas=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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