SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c8adfed59dde7ed2a3964909f7193c5567ba8241474da32253a94db508b86700' 
  AND token = 'JJEhlr+YTz8Q8K0j3KnCtk0nGN3VVJwwTt21A/geyhk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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