SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '987a84fc3090e5cdfd1cfb6d351b40f0db3b6698de968eeb10f0ef58fd847f2a' 
  AND token = 'a/Q2+vFlqif/8avCk9UPLFijmAR/osyFLmcteI+XWMg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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