SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45ffd234bcf630cd8ebcc701cab204f064d86786b7d787684c55c3b3f6eaa20d' 
  AND token = 'ZdLg/Orw/xvw+wxngjeLFRCRy3cmooewcssfQi3JgrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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