SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4d048d20665091f421e9e6497618881d2ea1924b1063ceec66709da66ff001d' 
  AND token = 'KkpQlfMjlR1GZUbct4OiN8tADamNE5e26fNlPKfnWDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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