SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ba6619964a9e4cb2e40ffc5ea522792fbb764c98074ba6343a2b4a66649c4fa5' 
  AND token = 'PM2Ua/HUHExRPvabuCTX3Ry8kiYIf9sLj7b/iZyinC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00010

JSON explain

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