SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1a3606f005d5c54e4e6d3abf1a894514e42d378f245cb4f3559a5a6da16ef73' 
  AND token = 'kuomoJcdtMgBPlLbY58DzNzzTFV4rlIRTRLgynAmA+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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