SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c16d8a12847f0484dbe33fa589962854b76a9d2ac5683a3c48ce7c353e833a3' 
  AND token = 'pAYdbTdmv3eUtJz5Hm29urwAGihKIH7l+pOKKB0LZNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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