SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77de1d43a525486859763c3088bd1c7b7b6bec7e3bef426e0e7397241f39947d' 
  AND token = 'h08p/kTEwyJYF1b+2v+afkPgRQn0B+DfAFDz8Ze9G0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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