SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fef2fc4fa586bf73688ee87a23392650b9f5118c09ad2729c14cd2537316c4b' 
  AND token = 'tDacxLF5YVLfmyb/xe/Sc2ywdL73YoqHb+EVLzrk/RQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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