SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e09c07f72ec08d129b3bd1f65ce98c470b98fbda01a25eff7ad8bf974f021673' 
  AND token = 'nL0NoKOb1BULr0YqelmoesszMiCscoHpCZAD6iSNY+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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