SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc06a26feeec2febf5b87ce36a4e87c1698d9c3a1fea7f90e10cdb957845e0eb' 
  AND token = 'e+eP6OeD2wBaXSNUxllAqhjqfJCLn+xBlfeeTNtDz4c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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