SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc791d8fa646db39f8f202f85fe8f34c74899d3877481eeb6122655a7385700e' 
  AND token = 'aUMHIOjwMoSLyvlWLioBkFsb51JKjxs59CxMihSav9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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