SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '63679f98aadf74dbc191d1cabca10b0f5c4fe0721cf207be6925d02b140027f5' 
  AND token = 'n/y2moAXQnklKCW+KSONguxR/C7x43dFtH8hAZWAvCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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