SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '796f734035052948843146330c9dc147fc843964b50f56fed908fb19b4ea1e14' 
  AND token = 'gXczvXbNLaJaqr+HnOkWZgAu7r49RXGwjvuY9PwzR1U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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