SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c63529972a4f6a20c8f73069819a2d2aab81f2ba6606e608d3043c53ce35887a' 
  AND token = 'XKLBWEBaabHMJB+n3DLWoh0sttoMElYyvlo4IXTloXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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