SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f774e11d51935634605de7fe30133a8c89b2d64c606e238afc65c66ecfeaf294' 
  AND token = 'LlhS5DWBYjO12sINf8YggZH1pXEUmeSs4d8yoFDDqqc=' 
  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"
    }
  }
}