SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c814095f3b91024ed6c8be4587cb741260bc4d912164e52e007cffdb9361d47a' 
  AND token = 'cOAKtuub8PfGdUmFzEvKbWMoN4tnqsYywhfdrZDg2hc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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