SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c8b6877fd216343f686c11be22d47f6c1a3c9f8888bd08584306efa186c08c8' 
  AND token = 'VoEtGJqIW8Esx7OuF43S83YqXprfToxxCGVoZZU1ChY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}