SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bece31855f5b554a3c678c05763d22db3255ecc1a6e65244a28bc2f67877921' 
  AND token = 'ILBgY5PCiMCDzKQvzatV+QrefEZ/FywyzPSA9ZYZiyo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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