SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '093f16be7f2357a55639b6ba92105d75a47f36f13ba6fb572c88b1189a01b42d' 
  AND token = 'kFPtnqc5E2ycaocHKSXs2gc2dVifDXRhkNyt8/KDGf0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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