SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55ec85c48956f6fd1777bb5177a58d1ed30c4918abe866803761a44c413764c5' 
  AND token = 'QtNZqEu3Hd4Bar2Mxrt9NgKUjyvuEud02EoaX2ifIwk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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